Process of detinning.



WALLACE SAVAGE, OF PIEDMONT, ALABAMA.

PROCESS OF DETINNING.

No Drawing.

Specification of Letters Patent. Application filed February 17, 1914. Serial No. 819,285.

Patented Oct. 13, 1914.

I have discovered that a coating of ordinary white tin may be changed to a dark amorphous non-adherent powder known as gray tin by the catalytic action of gray tin and that the change takes place most satisfactorily when gray tin isemployed in connection with a solution of a tin salt, preferably tin ammonium chlorid, SnCl NH Cl, which is commonly known as pink salt. The reaction occurs at ordinary atmospheric temperatures preferably however, below a temperature of 68? F. and somewhat more readily at a temperature ofrabout 32 F. I have found that practical commercial results can be obtained even at a temperature somewhat above 68 F., although a, lower temperature is preferred.

In using gray tin to transform white tin into gray tin, it may be applied to the white tin surface in a moist condition or preferably in the form of a slime. I prefer how ever to employ the gray tin 1n a solution of tin ammonium chlorid in the form of a slime. This slime may be advantageously produced by dissolving ten pounds of tin ammonium chlorid in 100 gallons of water and mixing with thisfsolution about 2500- pounds of gray tin.

The slime may be advantageously stirred or otherwise agitated while being used in the detinning operation but-I have found that satisfactory results are obtained by merely movlng the material to be detinned into and out of, or preferably through, the

slime.

As the white tin is transformed into the gray tin it separates from the metal in the form of a dark amorphous powder having a specific graviy of 5.2.

A part of the gray tin produced in the operation of the process is employed as a catalyzer in the detinning operatlon. The balance is transformed into white tin by melting.

While I have described in detail the preferred operation of my process it is to be understood that the proportions of the reagents and the temperatures may be varied within wide limit without departing from the spirit of my invention or the scope of the subjoined claims. I

Having described 'my claim 1. The process of detinning which consists in subjecting a coating of white tin to the action of a slime containing gray tin, whereby the white tin coating is transformed into gray tin.

2. The process of detinning which consists in subjecting a coating of White tin to the action of a slime containing a solution of a tin salt and a gray tin.

3. The process of detinning which consists in subjecting a coating of white tin. to the action of a: slime containing a solution of a basic halogen tin compound and gray tin.

4:. The process of detinning which consists in subjecting a coating of white tin to the action of a slime containing tin ammonium chlorid and gray tin.

In testimony whereof I afiix my signature in presence of two witnesses.

WALLACE SAVAGE.

invention; I

Witnesses:

JAMES L. CRAWFORD, C. L. PARKER. 

